B.Sc Entrance Exam

You should practice more questions and solve previous year questions. Also, you should revise you class 11th – class 12th concept.
Good luck.

To the best of my knowledge, there is no entrance test for B.Sc. In DU. The admission is conducted merit-based as determined by various cutoffs issued by DU.

Your question is not clear to me properly. Still I am trying to explain you. It depends on the different Institutes. Mainly autonomous Universities and colleges are taking exams.
For more details follow the link:
https://www.shiksha.com/college/subhash-chandra-bose-institute-of-higher-education-lucknow-40842

Kindly predict your college in this college predictor. JEE Main rank predictor is an online tool which predicts the candidates rank range and probable colleges based on the difficulty level of the examination, average marks scored in JEE Main and seats available in IITs, NITs, GFTIs, and other SFTIs. The rank predicted might not be accurate but it certainly does give an idea to the aspirant. Know your college admission chances based on your JEE Main Rank, Home State, Caste, Gender, etc. Here https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
Hope this helps.
Good Luck.

You can give NEET & AIIMS or any other medical entrance exams as admission criteria. Good luck.

https://www.shiksha.com/college/st-xavier-s-college/xavier-s-bms-entrance-exam-syllabus
Check The link to know about the syllabus and more. Good luck.

There is no specific syllabus for any entrance exam in B.Sc. They just ask anything in their 100 marks question paper. You have to prepare GK, GS, Hindi and English to clear their entrance. Only questions of 50 to 60 marks are asked from physics, chem. and bio (or maths). No specific syllabus is there.